John Treworgie was born in England, around 1618. Before coming to Newfoundland to serve as
governor, Treworgie worked as an agent at a trading post at Kittery, Maine, from 1635 to 1650.
During this period Treworgie may have had some business dealings with Newfoundland, but at
any rate he was probably familiar with the island since the Shapleigh family had exploited the
Newfoundland fishery for quite some time.

In 1651, Treworgie was named to a party of six commissioners to travel to Newfoundland to
arrest governor David Kirke, who was accused of various offences. They were also directed to
regulate the fishery and introduce a tax on fish and oil collected by foreign fishermen. When
Newfoundland was placed under the care and protection of Treworgie in 1653, he was already on
the island, which may indicate that had remained after arresting Kirke. As governor, Treworgie
was instructed to oversee the fishermen and the planters, to tax aliens, to erect fortifications and
to welcome any other complaints against Kirke.

Although Treworgie was able to stimulate trade and the fishery as well as supervise the planters
and the migratory fishermen, he and two other commissioners were arrested, in 1654, for taking
possession of David Kirke's property. Treworgie maintained that Kirke's possessions had been
returned to his wife, but was nonetheless found guilty in a first trial; however, Oliver Cromwell
requested a second trial, which in all likelihood cleared Treworgie's name, for he continued to
serve as governor until 1660.

In 1660, he asked for another term as governor and returned to England to collect supplies and
the six year's salary he claimed he was owed. However, because of the discord between Lord
Baltimore and the Kirke family over the ownership of Newfoundland, it is unlikely that Treworgie
ever returned to the island.